[Prenatal cytogenetic diagnosis at the Department of Medical Genetics GENNET-Klimentská].

Objective: Analysis of data from prenatal cytogenetic studies performed during 10 years.

Design: Retrospective analysis of cytogenetic results.

Setting: Cytogenetic laboratory, Department of Clinical Genetics GENNET, Prague.

Confocal fluorescence analysis of the depth and focus of cytogenetic preparations.

Objective: To characterize differences in the depth of fluorescent probes, to observe estimated depth levels (focal planes) on fluorescent in situ hybridization preparations by factor analysis of medical image sequences and to use cytogenetic techniques resulting in flat preparations of whole cells that are assumed to preserve the probes' access to their targets in the human nuclear interphase.

Study Design: We used labeling of the targets by the probes (sequences labeled by fluoroscein isothiocyonate [FITC]) in the nuclei, stained by propidium iodide. The investigation was performed on this model by three-dimensional (3-D) sequences of images obtained on a single photomultiplier detector of a confocal microscope by selection of emission between 510 and 550 nm and by (z) displacement.

Spectral and dynamic confocal fluorescence characterization of cytogenetic preparations.

Investigations were performed on fluorescent in situ hybridization (FISH) preparations to examine whether factor analysis of medical image sequences (FAMIS) can be used to isolate fluorescent probes by means of their spectral and/or extinction dynamic emission properties. FISH is used to track down chromosomes of interest in cell nuclei and mitoses. Cytogenetic techniques producing flat preparations of whole cells were assumed to preserve the probes' access to their targets.

Three-dimensional fluorescence in situ hybridization. Chromosomal studies on nuclei from cytogenetic preparations by confocal microscopy.

Objective: To determine the three-dimensional (3D) position of target sequences and chromosomal volumes in interphase human nuclei by confocal laser scanning microscopy (CLSM) by using the heterochromatin part of the long arm of human chromosome Y (HPLAHC) as a target for specific DYZ1 probes, then by D10Z1 probes specific to the centromere of chromosome 10.

Study Design: Fluorescence in situ hybridization information inside chromosomal preparations was obtained with FITC-labelled probes and propidium iodide (PI) as a DNA-specific stain. To have a control in the experiment, HPLAHC Y was taken as a model of a domain and the centromere of chromosome 10 as a model of a single centromere spot.

Prenatal identification of an isochromosome for the short arm of the Y i(Yp), by cytogenetic and molecular analyses.

A case of 45,X/46,X,+mar mosaicism was detected in a male fetus (27 weeks' gestation) referred for karyotype analysis following the observation of a short femur at the ultrasound scan. Analysis of 12 Y-chromosome loci by fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) demonstrated that the marker chromosome is of Y origin and corresponds to an authentic isochromosome for the short arm of the Y chromosome, i(Yp). The breakpoint on this marker is in YQ11.